frontiers / frontier
The frontier at a glance, assembled from accepted state: what the frontier holds, the strongest findings with their evidence, and the open and contested edges. Copy it straight into a grant, paper, or lab-meeting doc.
Brief export contract
A brief is a portable package over frontier state. It helps humans write, but the frontier remains the inspectable record.
accepted slice
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evidence table
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find evidence →
open work
Open questions, contested findings, gaps, and missing sources stay in the packet instead of being smoothed away.
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strongest findings (none formally accepted yet)
bibliography · 113 sources
export · markdown
# Pediatric high-grade glioma: distinct biology, distinct trials This frontier holds 115 findings (0 accepted) over 113 sources. ## Significance - H3K27M mutations (lysine-to-methionine substitutions at position 27 of histone H3.3 or H3.1) are present in 80-90% of diffuse midline gliomas and diffuse intrinsic pontine gliomas, occurring as early somatic events during pons development (reviewer:will-blair 2024) - FDA grants accelerated approval to dordaviprone (August 6, 2025) for pediatric (age ≥1 year) and adult patients with progressive H3K27M-mutant DMG post-prior therapy, based on 20% objective response rate and durable disease control; first-ever systemic therapy approval for this indication. (reviewer:will-blair) - Diffuse hemispheric glioma with H3 G34 mutation (H3G34R/V) represents a molecularly distinct entity from H3 K27M diffuse midline glioma, characterized by supratentorial hemispheric location, preferential occurrence in adolescents/young adults, and fundamentally different epigenetic landscape centered on H3K36 methylation dysregulation rather than H3K27me3 reduction. (reviewer:will-blair 2023) - H3K27M mutations drive global H3K27 hypomethylation and euchromatin remodeling, creating a pediatric-specific epigenetic landscape absent in typical adult GBMs. (reviewer:will-blair 2023) - Patients with H3K27M-mutant DMG demonstrate median overall survival of 10.1-14.4 months from diagnosis, with 5-year survival <2%, compared to 54-60 Gy focal radiotherapy as the only standard-of-care intervention showing modest survival benefit (reviewer:will-blair 2024) - BIOMEDE trial (N=233, diffuse intrinsic pontine glioma): None of three targeted-therapy arms (erlotinib, dasatinib, everolimus) + radiation exceeded radiotherapy alone on primary OS endpoint, revealing fundamental inadequacy of single-pathway inhibition in pediatric HGG. (reviewer:will-blair 2026) - Pediatric high-grade gliomas are biologically distinct from adult counterparts; histone H3 mutations (H3K27M, H3G34R/V) are present in approximately 80 percent of midline pediatric HGGs and are nearly absent in adult GBM, defining separate WHO 2021 entities. (agent:phgg-research-bot-2026-05-09) - H3K27M acts as a dominant-negative inhibitor of PRC2, impeding genome-wide H3K27me3 and H3K27me2 spread while paradoxically retaining methylation at CpG island regions, creating a globally silenced epigenome with selective promoter derepression (reviewer:will-blair 2019) - ONC201 (dordaviprone) demonstrates a 20% objective response rate and 40% disease control rate in pooled analyses of recurrent H3K27M-mutant diffuse midline glioma across five clinical trials (n=50), with median response duration of 11.2 months. (reviewer:will-blair) - ACVR1 R206H mutations occur in ~25% of DIPG cases and constitutively activate BMP signaling through the ALK2 kinase domain, independent of ligand binding. (reviewer:will-blair 2019) - Infant-type hemispheric gliomas harbor RTK fusions (ALK 47%, NTRK 22.5%, ROS1 20.4%) in 86.5% of cases, versus rare fusions in adult GBM. (reviewer:will-blair 2026) - Adult Stupp protocol (concurrent TMZ + radiotherapy) produced no survival benefit in pediatric GBM/HGG (ACNS0126 trial), unlike its 14.6-month OS benefit in adults. (reviewer:will-blair 2011) ## Contested - Patients with H3K27M-mutant DMG demonstrate median overall survival of 10.1-14.4 months from diagnosis, with 5-year survival <2%, compared to 54-60 Gy focal radiotherapy as the only standard-of-care intervention showing modest survival benefit - ONC201/GsONC201 treatment in 28 H3K27M-mutant DIPG patients achieved median overall survival of 18 months; reirradiation-treated patients showed OS of 22 months versus 12 months without reirradiation, suggesting synergy between ONC201 and radiation - Thalamic location and older age (adult vs pediatric) are independent favorable prognostic factors for ONC201 response and survival; thalamic tumors show significantly better outcomes in real-world compassionate use cohorts (n=174). - H3K27M disrupts PRC2-mediated H3K27 trimethylation globally via sequestration of the complex at poised enhancers, causing epigenetic dysregulation and altered chromatin compaction; ONC201 reversal of H3K27M phenotype operates through ClpP-stress, not PRC2 restoration. - Pediatric H3K27M-mutant DMG patients exhibit shorter median overall survival (3.65 months, 95% CI 2.73-4.40) than adults (7.37 months, 95% CI 4.27-13.90); low KPS and omission of trimodality therapy independently predict poor outcomes in both age groups. - H3G34-mutant hemispheric gliomas arising adjacent to prior radiation fields or in patients with germline TP53 mutations (Li-Fraumeni syndrome) suggest a link to cancer predisposition syndromes and radiation-associated tumorigenesis; routine germline sequencing is warranted in pediatric H3G34 cases. - GD2-CAR T cells administered intravenously and/or intracerebroventricularly achieve clinical and radiographic responses in 3 of 4 H3K27M DIPG patients in a phase I trial, without on-target off-tumor toxicity. - H3K27M mutations drive global H3K27 hypomethylation and euchromatin remodeling, creating a pediatric-specific epigenetic landscape absent in typical adult GBMs.